The invention relates to a folding top for motor vehicles of the type having a top frame which comprises lateral top supports and a rear hoop, having a storage position of the top in an associated top box, into which it can be lowered by folding back the upright top supports about a main axis, having an articulation, spaced relative to the main axis, of the lateral legs of the rear hoop on the frame members which are jointly moved via the top supports, whereby the rear hoop is displaced backwards relative to the main axis during the lowering process, and having a rearward widening of the top box behind the top box aperture, into which the rear hoop projects when the top is lowered.
Such a folding top is already to be found as known in, for example, Patent Application P 41 29 493.921, the lateral legs of the rear hoop being articulated on the assigned top support at a substantial distance from the main pivot axis of the top. Because of this articulation, the rear hoop, during the process of lowering of the top, executes a pivoting movement, upon which a rearward displacement movement is superimposed. For design reasons, the aperture of the top box is arranged so that the rear hoop can only be folded into the latter if, before the folding-back of the top supports, it has been folded down out of its upright intermediate position into a lowered pivot position. When the top supports are subsequently folded back, it dips through the top box aperture and finds the space for further backward displacement in the top box itself, because the rear wall of the top box is correspondingly recessed rearwards within the top box aperture.
If this intended folding sequence is not followed, for example by an unskilled operator, and the top is moved back while the rear hoop is still erected, the rear hoop fails to fit through the top box aperture and impacts on the bodywork.
Apart from the fact that the process of lowering of the top cannot thus be readily completed, energetic rearward movement of the top may even cause damage to the top itself or to the parts of the bodywork on which impact takes place.
An object of the invention is therefore the further development of a folding top of the generic type, whereby incorrect operation during manual lowering of the top into the top box as a result of nonobservance of the intended sequence for folding the top supports and rear hoop can be prevented with adequate reliability.
This object is achieved by providing preferred embodiments of the invention according to an arrangement wherein the top supports of the top are retained, when the rear hoop is upright, via locking devices which prevent their folding-back movement and whose locking action can be cancelled by an advance rearward pivoting movement of the rear hoop, the pivot angle of the advance being such that, when the top supports are subsequently folded back, contact-free dipping of the rear hoop through the top box aperture is guaranteed.
A particularly reliable procedure control can be achieved according to certain preferred embodiments by means of a locking mechanism as a blocking means which is automatically unlocked, purely mechanically, via the rearward pivoting movement of the rear hoop.
A particularly favorable locking mechanism, in terms of cost and weight, comprises a pivot member mounted on the top support which, in the locked state, interacts with a retaining component by engaging behind it and can be unlocked via the advance pivoting movement of the rear hoop. In this arrangement, any conventional transmission means, such as a cable with return springs, rams with return springs, etc. , are suitable for linking the movements of the pivot member and rear hoop.
A particularly expedient transmission means is provided in certain preferred embodiments, including a lever which is resistant to tensile and compressive forces, is connected in an articulated manner to the assigned leg of the rear hoop, and can drive the pivot member in both the locking direction and the unlocking direction. Thus it is possible to dispense completely with a return spring. Such a lever could be, for example, a connecting rod.
In order to permit a particularly compact arrangement or design of the locking mechanism, the pivot member is designed as a two-armed lever and the rearward projecting lever arm forms the lever which is articulated by its end on the associated leg of the rear hoop.
In respect of production engineering aspects and for the purposes of simplified retrofitting of the locking mechanism, it is advantageous if the bearing point for the articulation of the lateral legs of the rear hoop, which is necessary in any event, is also used for mounting the pivot member.
In order to engage behind the retaining component, the pivot member is preferably provided with a hook-shaped end region which acts as a catch coupling and can thus be moved as far away as desired from the retaining component in the unlocking direction. Moreover, as a result of appropriate sizing of the extent of the hook, unlocking can be ensured after a precisely defined angle of pivot of the pivot member.
A locking bolt which passes transversely through the pivot plane of the pivot member is provided as a retaining component which also durably resists the violent stresses of everyday use.
Preferably, the end region of the pivot member has a U-shaped locking aperture which is matched to the diameter or cross-section of the locking bolt. As a result of this matching, the locking bolt is engaged by the end region of the pivot member in the locking position, with circumferential play, as a result of which a correspondingly easy pivoting of the pivot member relative to the locking bolt is possible. Furthermore, the clear cross-section of the elongate locking aperture enlarges to a certain extent in a wedge-shaped manner towards the exit side, in order to bring about automatic centering of the locking member when it dips into the locking aperture.
In order that it should be possible for the lever arm of the locking member, provided with the hook-shaped end region, to be of relatively short design, the pivot member interacts with a retaining component which projects from a main connecting rod, coupled to the top support, in the manner of a parallelogram linkage. In this arrangement, the retaining component and pivot member are so arranged relative to each other that the constrained motion of the connecting rod parallelogram defined by the main connecting rod and the top support is cancelled by the pivot member connection while the connection remains.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.